136 PHILOSOPHICAL TRANSACTIONS. [aNNO 1737- 



Observations of two Parhelia, or Mock-Suns, seen at Witlemherg, in Saxony, 

 on Dec.3\, 1735. 0.5. By John Frid. fVeidler, F. R. S. i^c. N° 445, 

 p. 54. 



Dec. 31, 1735, o. s. a little after 10 in the morning, being informed that 

 several suns were seen in the heavens, Mr. W. went into his garden, and 

 immediately saw near the sun s, on its left or western side, the parhelion b, 

 as large as the true sun, fig. 15, pi. 5. This mock-sun was amidst small, 

 round, white clouds, set thick, and close to one another. The middle of this 

 mock-sun shone with so great a light, that the naked eye could not bear it ; 

 so that he viewed it attentively through a glass darkened with the smoke of 

 a wax-candle. The light of the parhelion b appeared much weaker than that 

 of the true sun. Its circumference, facing the sun, was red : but that part of 

 the stream fg, which was towards the sun, was purple. Within the red 

 border appeared the other colours of the rainbow, as yellow, green and azure ; 

 the stream bh was likewise embellished with red and yellow. Both edges of 

 this were reddish, and its middle yellowish. The sun s was 15°-f above 

 the horizon ; and its image b was near the same altitude : the distance from s 

 to B was '20°: the arch fg was near 6° in length. Most of the south- 

 ern part of the hen)ibphere was overspread with white clouds, interspersed 

 with some darker ones. There were some thin clouds before the true sun, 

 through which its rays easily passed. When thicker clouds surrounded the 

 sun, the brightness of the parhelion was lessened : the parhelion was now and 

 then hidden by dark clouds. Soon after first observing the parhelion b, was 

 seen the beautiful rainbow ode, parallel to the horizon, with its horns turned 

 to the north. It had the usual colours of the rainbow, all very distinct. The 

 purple was on the side facing the sun ; next to it was the yellow, then the 

 green, and last the azure. The point d was Q\° distant from the horizon; 

 therefore the diameter of the rainbow was 58° : however, only a part of the 

 rainbow ode was seen, the ends of which were sometimes but 38° from one 

 another: for more or less of it appeared at different times, but scarcely above 

 a 4th part of its circumference at any time. It lasted till the sun and most 

 part of the sky was overcast by thick clouds. The thickness of the rainbow 

 CK, as well as I could estimate by the bare eye, was 1° of a great circle. 



From another place, whence he had a full view of tl)e hemisphere, a little 

 before 11 , he saw another parhelion a to the east, 20° from the sun, as the 

 former was, and raised 15° above the horizon. This mock-sun was not infe- 

 rior to the other b, in brightness, for the naked eye could no more bear it 



